/* Base Reset & Variables */
:root {
  --bg-color: #ffffff;
  --surface-color: #ffffff;
  --panel-bg: #fafafa;
  --border-color: #e5e7eb;
  --border-color-focus: #111827;
  --text-primary: #111827;
  --text-secondary: #4b5563;
  --text-muted: #9ca3af;
  --accent-color: #111827;
  --accent-hover: #374151;
  --toast-bg: #111827;
  --toast-text: #ffffff;
  --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", Roboto, "Inter", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  --radius: 8px;
  --transition: all 0.15s ease;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-base);
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  padding: 24px 16px;
}

.container {
  max-width: 960px;
  margin: 0 auto;
}

/* Header */
.header {
  margin-bottom: 24px;
  text-align: center;
}

.title {
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.subtitle {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* Main Converter Card */
.converter-card {
  background: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
  padding: 20px;
  margin-bottom: 24px;
}

/* Controls Bar */
.controls-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 16px;
}

.mode-selector {
  display: inline-flex;
  align-items: center;
  background: #f3f4f6;
  border-radius: 6px;
  padding: 3px;
  gap: 2px;
}

.mode-btn {
  background: transparent;
  border: none;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 6px 14px;
  border-radius: 4px;
  cursor: pointer;
  transition: var(--transition);
}

.mode-btn.active {
  background: #ffffff;
  color: var(--text-primary);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.06);
}

.swap-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: 6px;
  border-radius: 4px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.swap-btn:hover {
  background: #e5e7eb;
  color: var(--text-primary);
}

.options-group {
  display: flex;
  align-items: center;
  gap: 8px;
}

.option-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.select-box {
  font-family: inherit;
  font-size: 0.85rem;
  padding: 6px 10px;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  background: #ffffff;
  color: var(--text-primary);
  outline: none;
  cursor: pointer;
  transition: var(--transition);
}

.select-box:focus {
  border-color: var(--border-color-focus);
}

/* Notice Bar */
.notice-bar {
  background: #f9fafb;
  border: 1px solid #e5e7eb;
  border-radius: 6px;
  padding: 8px 12px;
  margin-bottom: 14px;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.detected-type {
  font-size: 0.75rem;
  font-weight: 500;
  color: #4b5563;
  background: #f3f4f6;
  padding: 2px 6px;
  border-radius: 4px;
}

/* IO Grid */
.io-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

@media (max-width: 680px) {
  .io-grid {
    grid-template-columns: 1fr;
  }
}

.panel {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: #ffffff;
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 12px;
  background: #fafafa;
  border-bottom: 1px solid var(--border-color);
  border-top-left-radius: 5px;
  border-top-right-radius: 5px;
}

.panel-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
}

.panel-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.action-link {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 0.8rem;
  cursor: pointer;
  text-decoration: underline;
  padding: 0;
}

.action-link:hover {
  color: var(--text-primary);
}

.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-primary);
  cursor: pointer;
  transition: var(--transition);
}

.copy-btn:hover {
  background: #f3f4f6;
  border-color: #d1d5db;
}

.copy-btn.copied {
  background: #111827;
  color: #ffffff;
  border-color: #111827;
}

.textarea {
  width: 100%;
  height: 180px;
  padding: 12px;
  border: none;
  resize: vertical;
  font-family: inherit;
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--text-primary);
  background: #ffffff;
  outline: none;
}

.output-textarea {
  font-family: var(--font-mono);
  background: #fafafa;
}

.panel-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 6px 12px;
  border-top: 1px solid #f3f4f6;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.copy-hint {
  color: #059669;
  font-weight: 500;
}

/* Reference Table Section */
.table-section {
  background: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
  overflow: hidden;
  margin-bottom: 24px;
}

.table-toggle-btn {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 18px;
  background: #ffffff;
  border: none;
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-primary);
  cursor: pointer;
  transition: var(--transition);
}

.table-toggle-btn:hover {
  background: #f9fafb;
}

.toggle-title {
  display: flex;
  align-items: center;
  gap: 8px;
}

.chevron {
  transition: transform 0.2s ease;
}

.table-toggle-btn.open .chevron {
  transform: rotate(180deg);
}

.table-wrapper {
  padding: 0 16px 16px 16px;
  border-top: 1px solid var(--border-color);
}

.table-desc {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin: 12px 0 8px 0;
}

.table-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.cipher-table {
  width: 100%;
  border-collapse: collapse;
  text-align: center;
  font-size: 0.88rem;
  background: #ffffff;
}

.cipher-table th,
.cipher-table td {
  border: 1px solid #e5e7eb;
  padding: 7px 4px;
  min-width: 38px;
}

.cipher-table th {
  background: #f9fafb;
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.cipher-table td.row-num {
  background: #f9fafb;
  font-weight: 600;
  color: var(--text-secondary);
  font-size: 0.8rem;
}

.cipher-table td.cell-item {
  cursor: pointer;
  transition: background 0.1s ease;
  user-select: none;
}

.cipher-table td.cell-item:hover {
  background: #e5e7eb;
}

.cipher-table td.cell-item:active {
  background: #d1d5db;
}

.cell-char {
  font-weight: 500;
  color: var(--text-primary);
  display: block;
}

.cell-code {
  font-size: 0.65rem;
  color: var(--text-muted);
  display: block;
}

/* Footer */
.footer {
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
  padding: 16px 0;
}